This was the election result last time in Oldham West and Royton, a seat in England’s north which has a crucial by-election today.

General Election 2015 results

Electorate: 72,341

Turnout: 59.63%

Result: Lab hold

Swing: 4.03% swing Lab to UKIP

Party

2010

2015

Change

Lab

45.45%

54.78%

9.33%

UK Independence Party (Ukip)

–

20.61%

–

Cons

23.66%

18.98%

-4.68%

Lib Dem

19.09%

3.68%

-15.41%

Green

–

1.94%

–

This is absolutely rock solid Labour Party territory. Oldham West has voted Labour at every general election since 1950 (though the Tories did win a 1968 by-election).

The MP for much of that time was the veteran (and well-respected) left winger Michael Meacher, who with 45 years of interrupted service would have been in line to become Father of the House, had not Gerald Kaufman been sworn in first in 1970 because he was late for a party.

For the Labour Party to lose Meacher’s seat, or even to nearly lose it, would be an almost unparalleled political earthquake, regardless of the efforts of the Party’s leadership and local activists to “talk down” their likely result in advance, as they have been doing with ever-more-frantic determination as the by-election has gone on.

Whatever the precise nature of the result, we predict the following outcomes:

The result will be bad enough that the Parliamentary Labour Party will turn on their leader, Jeremy Corbyn, thus putting themselves further at odds with their own membership. Despite his recent elevation to the top job Corbyn is probably already fatally wounded by his obvious inability to translate his popularity with the party’s members (and key unions) into any rise in his personal popularity in the country as a whole. Indeed, it’s worse than that. His approval levels have gone backwards. He already looks like a dead man walking.

Hilary Benn

But the Labour Party has used up most of its eligible more centrist leadership contenders who all got thoroughly thrashed by Corbyn. So if anyone is to replace him, we are guessing they will need to come from the left of the party, or at least from an impeccable left heritage. That might be, for example, Hilary Benn, son of the redoubtable now-deceased Labour legend Tony Benn, although Benn the Younger now finds himself in an interesting position. His speech in favour of British military action in Syria has been widely praised, and it brands him “a realist” as well as a left winger, thus making him more acceptable to the Parliamentary party as a whole. However his support for bombing will also make him instantly toxic with many of the party’s rank and file. How he squares that circle will determine his future success.

Whoever steps up to the plate, Labour are undoubtedly in an unholy mess.

UKIP are going to do very, very well. Anti-immigration, anti-EU sentiment still runs very high – including with white, working class voters that could normally be relied upon to back Labour, all things being equal – and recent events in Paris have done nothing to reassure people. UKIP may well win the seat or come within a few hundred votes of doing so.

Everything will depend on turnout. If the Labour vote turns out – and especially if its immigrant (mainly Bangladeshi) supporters turn out – then UKIP will not win. But they will do very well nevertheless. If the turnout falls into the low 40%s or even lower then look out.

What’s more, the momentum is with UKIP. A recent online poll on a story on the by election had two-thirds of people thinking they would win the seat. Now such polls are not scientific in any sense, of course, but they are nevertheless often indicative. And the indication is that Labour are on the nose.

The position of the Lib Dems is interesting, too, for those who hold an affection for the minority party that took such a shallacking at the last election after their Coalition with the Conservatives saw their support tumble.

They have thrown a lot of effort into the campaign, and need to see an up-tick in their fortunes to indicate that they are not a completely busted flush as far as British parliamentary politics is concerned. In the relatively recent past this would have been a seat that the Lib Dems would have eyed with some relish – indeed, they viewed any by-election opportunity with relish – but their recent by-election performances have been largely forgettable, and their vote collapse at the last general election in this seat was near-terminal.

In the new, cold, harsh world that faces them, Lib Dem activists would be mildly comforted by a result that saw them hold their deposit (anything above 5%) and have been bullishly talking about maybe hitting a 10% mark. That 10% would cause near rejoicing to break out amongst the Lib Dem members, with their bright new leader and plenty of new members, is a perfect weathervane as to how truly disastrous their plight has actually become.

Natural supporters of the Liberal Democrats – and especially their activists – are deeply divided over their party’s general support for the action in Syria. The dispute between their remaining parliamentary rump and their core supporters could hardly have come at a worse moment for both party worker morale or the morale of those left-wing, tertiary-educated voters who have clung to their unique strand of liberalism in the United Kingdom.

The Conservatives are also running a candidate, and are doing well in national polls. They fell behind UKIP last time, and right wing voters may well defect to UKIP this time perceiving them having a better chance of unseating Labour. But our guess is actually that something more subtle will happen.

The parliament’s debate on bombing Syria has polarised opinion in the country in a variety of ways. The Conservatives have largely looked strong on foreign affairs, and that never hurts a sitting right wing government. Their polling actually has them up a couple of percentage points in recent weeks. Ironically, this may persuade some of their natural supporters to stay true to them, which will, in turn, hurt UKIP’s chances.

Public opinion has been moving against intervention in Syria, for sure, but there’s not a sign of it helping Jeremy Corbyn with the wider public, or of it hurting Conservative support. As we have said, while Cameron’s Tories see their support steady or rising, Corbyn’s own ratings are down – 24% of people now think he is doing well as leader, down from 30% last week; 65% think he is doing badly.

It will escape no psephologists attention that the broadacre Lib Dem vote at the last General Election was 7.9% so they have actually gone backwards since May, but then again their Oldham vote was even lower. Nor will it escape anyone’s attention that UKIP on 16% are higher than they were at the last GE on 12.7%.

What does it all mean? Well, our predictions for the election are as follows:

Labour will do badly, but largely through abstentions from a disinterested electorate who are unimpressed with Corbyn. They will hold the seat – just. It also won’t help – yes, we’re serious – that it’s going to rain. Look for a Labour winning margin of 2-3%.

UKIP will take votes from the Lib Dems and the Greens, and from some disaffected Labour voters, and from some canny tactical-voting Tories, but will fall short. We might be wrong – they might do even better than we predict, but we genuinely doubt it. For one thing, very little smart money is flowing onto them at the various bookmakers, and betting is a hugely accurate view of likely electoral outcomes.

The Lib Dems may gain a point or two over their abysmal May result but will lose their deposit, again, which will be hard on a hard-working and attractive candidate, and harder still on the new party leadership, and their party will be cast into gloom. And with good reason.

This is why we opined, publicly, that they should have kept their powder dry – pick and choose their fights, in other words – and to focus on building up activists and resources in seats they absolutely need to re-take in 2020.

Many of their membership will be in denial after this by-election turns into a fiasco, but the simple fact is that even if they might not have expected to win a by-election here in the past they would have expected to see their renowned by-election fighting machine deliver them a substantial uplift. That simply will not happen.

They will beat the Greens though, and probably the Monster Raving Loony Party. But not definitely.